JPH0820634A - Polyarylate and its production - Google Patents

Abstract

PURPOSE:To obtain a polyarylate low in residual salt content. excellent in optical properties, esp. transparency, useful for various optical parts, and excellent in the phase separability between aqueous and organic solvent phases after the interfacial polymerization, by carrying out interfacial polymerization using a specific phase-transfer catalyst. CONSTITUTION:This polyarylate is obtained by interfacial polymerization between an alkaline aqueous solution of an aromatic diol and an organic solvent solution of an aromatic dicarboxylic halide using a quaternary ammonium salt of formula I (R1-R3 are each n--butyl; R4 is an alkyl such as methyl or ethyl or aromatic substituted alkyl such as benzyl; X is Cl, Br, I or HSO4) or phosphonium salt of formula II as phase-transfer catalyst (pref. tributylbenzylammonium). This polyarylate has the following characteristics: inherent viscosity: 0.35-0.80; terminal carboxyl value: <=20mol/ton; and residual alkali metal level: <=30mg/kg.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low molecular weight polyarylate having less residual salts and excellent transparency, and a method for producing the same.

[0002]

2. Description of the Related Art Polyarylates consisting of residues of dihydric phenols, especially residues of 2,2-bis (4-hydroxyphenyl) propane and residues of terephthalic acid and / or isophthalic acid are already well known as engineering plastics. There is. As a method for producing such a polyarylate, an interfacial polymerization method, a solution polymerization method, a melt polymerization method and the like are known. Among them, the polyarylate produced by the interfacial polymerization method has good color tone and physical properties. . The interfacial polymerization method is a method of mixing an alkaline aqueous solution of a dihydric phenol and an organic solvent solution of an aromatic dicarboxylic acid with stirring to generate a polymer, but according to this method, after the completion of the polymerization reaction,
The operation of separating the aqueous phase containing a large amount of salts from the organic solvent phase in which the polymer is dissolved is essential for improving the physical properties of the polymer. However, when a low molecular weight polymer is produced by this method, there are often problems that the aqueous phase and the organic phase form a stable emulsion, and in some cases, phase separation does not occur even if stirring is stopped. there were. When the phase separation is poor, salts remain in the polymer after isolation, and when a molded product is produced using such a polymer, it appears as haze.

In order to solve such a problem, for example, Japanese Patent Publication No. 53-2679 discloses a method of breaking the emulsion by making the pH of the aqueous phase alkaline.
Japanese Patent No. 2133 discloses a method of treating with an aqueous solution containing acetone or a lower aliphatic compound soluble in water. According to these methods, the phase separation property can be improved to some extent, but an alkali, acetone or the like to be added is necessary, and there is a problem that the amount of impurities in the polymer is increased in some cases. JP-A-48-55286 discloses a method using a centrifuge, and JP-B-55-41249 discloses a method of devising stirring conditions. According to these methods, it is possible to improve the phase separation property, but there is a problem that a special device is required for manufacturing.

Further, depending on the state of the emulsion, there is a problem that a clear organic solvent phase cannot be obtained even by using a centrifugal separator. Japanese Patent Fair 1-2285
Japanese Patent Publication No. 2 discloses a method of breaking the emulsion by adding a monoacid halide at the end of the polymerization. According to this method, the phase separation property can be improved, but there is a problem in that unreacted monoacid halide remains and the mixing of impurities is essentially unavoidable. Japanese Patent Publication No. 12974/1990 discloses that the phase separation property is improved by using an oil-soluble phase transfer catalyst during polymerization. According to this method, it is possible to improve the phase separation property to some extent, but there is a problem that the phase separation deteriorates depending on the conditions, and if the oil solubility is too strong, it may remain in the polymer even after purification. However, there is a problem in that the complex with the monomer is hard to dissolve in the alkaline aqueous solution, and thus precipitates as a precipitate.

Further, an excessive amount of alkali is required to dissolve the precipitate, and the excessive amount of alkali accelerates the hydrolysis of acid chloride to increase the carboxyl value of the polymer, resulting in poor phase separation. However, there is a problem that it is difficult to purify the polymer after the polymerization. The above-mentioned method is a method assuming an emulsified case, and although the phase separation property can be improved to some extent, each method has advantages and disadvantages, and the cause of poor phase separation property is unknown. Therefore, it could not be an essential solution.

[0006]

In view of the above situation, an object of the present invention is to provide a low molecular weight polyarylate having less residual salts and excellent transparency, and a method for producing the same, which has excellent phase separation property after interfacial polymerization. Is provided.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to obtain a low molecular weight polyarylate having excellent phase separation property after polymerization during interfacial polymerization and excellent transparency. It was found that the emulsion generated when the separation is poor is due to the surface-active effect of polyarylate itself, that is, the quality of phase separation is determined by the balance between the main chain of polyarylate and the hydrophobic / hydrophilic balance of the ends. It was Regarding the hydrophobic / hydrophilic balance of polyarylate, it was found that the carboxyl value and the amount of alkali metal of polyarylate are indicators of the quality of the phase separation property. The higher the carboxyl value and the more the amount of residual alkali metal, the more It was found that the hydrophilicity of the polymer is increased, resulting in poor phase separation. Further, it was found that a specific phase transfer catalyst may be used during interfacial polymerization in order to produce a polyarylate having a low carboxyl value and a small amount of residual alkali metal. The present invention has been reached based on these findings.

That is, the gist of the present invention is a polyarylate synthesized by an interfacial polymerization method from an aromatic diol and an aromatic dicarboxylic acid halide, and having an inherent viscosity value of 0.35 to 0.80, Carboxyl number is 2
0 mol / ton or less and the amount of residual alkali metal is 3
It is a polyarylate characterized in that it is 0 mg / kg or less, and this polyarylate has the formula (1) when interfacial polymerization is carried out from an alkaline aqueous solution of an aromatic diol and an organic solvent solution of an aromatic dicarboxylic acid halide. The quaternary ammonium salt or the phosphonium salt of formula (2) can be used as a phase transfer catalyst for polymerization.

[0009]

Embedded image

[In the formulas (1) and (2), R _{1 to} R ₃ are n
A butyl group, R ₄ is an alkyl group such as a methyl group or an ethyl group, or an aromatic substituted alkyl group such as a benzyl group, X is Cl,
Represents Br, I, HSO ₄ . ]

Hereinafter, the present invention will be described in detail. Aromatic diols that can be used to produce the polyarylate of the present invention include hydroquinone, resorcinol, 1,3-
Dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, bis (4-hydroxy) Phenyl) methane, bis (2-hydroxyphenyl) methane, 1-
(2-hydroxyphenyl) -1- (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfide, bis (4-)
Hydroxyphenyl) sulfoxide, bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) -p-diisopropylbenzene, bis (3,5-dimethyl-4-hydroxyphenyl) methane , Bis (3-
Methyl-4-hydroxyphenyl) methane, bis (3,3
5-dimethyl-4-hydroxyphenyl) ether, bis (3,5-dimethyl-4-hydroxyphenyl) sulfone, bis (3,5-dimethyl-4-hydroxyphenyl) sulfide, 1,1-bis (4-hydroxy) Phenyl) ethane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -1- Phenylethane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, 2, 2-bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (3-chloro-4-hydroxyphenyl) propa , 2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane, 2,2-bis (3-bromo-4-hydroxyphenyl) propane,
2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, 1,1,1,3,3,3-hexafluoro-2,2-bis (4-hydroxyphenyl) propane, 4,4 '-Dihydroxybiphenyl, 3,3',
Examples thereof include 5,5′-tetramethyl-4,4′-dihydroxybiphenyl and 4,4′-dihydroxybenzophenone, and these may be used alone or in combination of two or more. Of course, the compounds are not limited to those exemplified here, and any aromatic diol can be used for producing the polyarylate of the present invention.

As the aromatic dicarboxylic acid halide that can be used for producing the polyarylate of the present invention, terephthalic acid halide, isophthalic acid halide, orthophthalic acid halide, diphenic acid halide, 1,4-
Naphthalenedicarboxylic acid halide, 2,3-naphthalenedicarboxylic acid halide, 2,6-naphthalenedicarboxylic acid halide, 2,7-naphthalenedicarboxylic acid halide, 1,8-naphthalenedicarboxylic acid halide, 1,5
Examples thereof include naphthalenedicarboxylic acid halides, halides of aromatic dicarboxylic acids in which an aromatic nucleus is substituted with an alkyl group or a halogen group, or a mixture in which these are appropriately mixed in the range of 25 to 75%. Examples of halides include chlorine, bromine and iodine, and among these, chlorine is preferable.

In producing the polyarylate of the present invention, a monovalent aromatic hydroxy compound, an aromatic acid halide, an aromatic haloformate or the like can be used in order to adjust the molecular weight and the balance of the end groups. Specific examples of the compound include phenol, o, m, p-cresol, o, m, p as the monovalent aromatic hydroxy compound.
-Alkylphenols such as ethylphenol, o, m, p-propylphenol, o, m, p-tert-butylphenol, pentylphenol, hexylphenol, octylphenol, nonylphenol and o,
Examples thereof include halogenated phenols such as m, p-phenylphenol, o, m, p-chlorophenol, and the like. Specific examples of monovalent carboxylic acid halides include:
Benzoic acid, o, m, p-methylbenzoic acid, o, m, p-
As aromatic haloformates such as t-butylbenzoic acid, aromatic carboxylic acids such as o, m, p-chlorobenzoic acid, and the like, phenylhaloformate, o, m, p-methylphenylhaloformate, o, m, Examples thereof include p-t-butylphenyl haloformate and o, m, p-chlorophenyl haloformate.

The polyarylate of the present invention has a temperature of 25 ° C.
The inherent viscosity value measured at a concentration of 1 g / dl in 1,1,2,2-tetrachloroethane was 0.35 to 0.80.
And preferably in the range of 0.4 to 0.70. If the inherent viscosity value is less than 0.4, sufficient mechanical properties cannot be obtained. If it exceeds 0.7, the melt viscosity becomes high and molding becomes difficult.

Furthermore, the polyarylate of the present invention comprises 20
It has a carboxyl value of not more than mol / ton. It is preferably 15 mol / ton or less. Carboxyl number is 20
If it exceeds mol / ton, the phase separation property after interfacial polymerization becomes poor depending on the stirring conditions and the like, and polyarylate having more excellent transparency cannot be obtained.

In the present invention, the terminal carboxyl value represents the amount of the terminal carboxyl group, and a publicly known method can be adopted as the measuring method. Specifically, it can be measured by dissolving polyarylate in a mixed solvent of benzyl alcohol and chloroform and performing neutralization titration with an aqueous KOH solution of benzyl alcohol.

The polyarylate of the present invention has a residual alkali metal content of 30 mg / kg or less. When the residual alkali metal amount exceeds 30 mg / kg, the phase separation property after interfacial polymerization is deteriorated, and a polyarylate having more excellent transparency cannot be obtained. The polyarylate of the present invention is produced by stirring and mixing an organic solvent such as a halogenated hydrocarbon having an aromatic dicarboxylic acid halide dissolved therein with an aqueous solution of an alkali having an aromatic diol and a phase transfer catalyst dissolved therein. You can Polymerization temperature is 0-40
The temperature and the polymerization time are 0.5 to 24 hours. After completion of the polymerization, stirring is stopped and the aqueous phase and the organic phase are separated. Furthermore, the polymer dissolved in the organic phase is purified and recovered by a known method to obtain polyarylate.

Further, examples of the alkali used in producing the polyarylate of the present invention include sodium hydroxide and potassium hydroxide. The amount of alkali used is 1. The molar number of the aromatic diol and the phenolic hydroxyl group, which is a monovalent aromatic hydroxy compound, is 1.
It is preferably in the range of 01 to 2.5 times. 1.01
If it is less than 2.5, the aromatic diol cannot be completely dissolved, and if it exceeds 2.5, it tends to be difficult to remove salts even if the phase separation property is good, and the residual alkali metal amount in the polymer is 30 mg / As it becomes difficult to make it less than or equal to kg, hydrolysis of acid halide during polymerization easily occurs,
It is not preferable because the carboxyl value tends to increase and the phase separation tends to deteriorate.

Furthermore, the halogenated hydrocarbon which can be used for producing the polyarylate of the present invention includes:
Halogenated hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, 1,2-dichloroethane, trichloroethane and tetrachloroethane can be exemplified.

Examples of the phase transfer catalyst that can be used for producing the polyarylate of the present invention include those represented by the formulas (1) and (2). [R _{1 in} Formulas (1) and (2)]
To R ₃ are n-butyl groups, R ₄ is an alkyl group such as a methyl group or an ethyl group, or an aromatic substituted alkyl group such as a benzyl group,
X represents Cl, Br, I, HSO ₄ . When R _{1 to} R ₃ have a smaller number of carbon chains than the n-butyl group, the reaction activity is low, and as a result, only polyarylate having a high carboxyl value can be produced. Further, if the number of carbon chains is too large, precipitation will occur when the aromatic diol is added to an alkaline aqueous solution, and an excessive amount of alkali is required to dissolve it. As mentioned above, excess alkali promotes hydrolysis of the acid halide. Specific examples of the compound include iodide such as tributylbenzylammonium, tetrabutylammonium, tetrabutylphosphonium, bromide, chloride and quaternary ammonium salt of hydrogensulfate, and a mixture thereof. Of course, the compounds listed here are examples, and any compound satisfying the formula (1) or the formula (2) can be used in the production of the polyarylate of the present invention.

[0021]

EXAMPLES The present invention will be described in more detail with reference to the following examples. The following methods were used to evaluate the characteristics of the present invention.

1) Aqueous Phase Transfer Rate (Evaluation of Phase Separation) After interfacial polymerization of polyarylate, stirring was stopped to 1
The mixture was allowed to stand for 0 minute and the aqueous phase and the organic phase were naturally separated. The volume of the clarified aqueous phase was measured. The rate of transfer of the aqueous phase to the organic phase was defined by the following equation.

[0023]

[Equation 1]

2) Carboxyl number 0.15 g of polyarylate is precisely weighed in a test tube and dissolved by heating in 5 ml of benzyl alcohol. Chloroform 10
After mixing ml with the benzyl alcohol solution of the polymer, phenol red was added as an indicator, and the carboxyl value was determined by neutralization titration with a 0.1 NKOH benzyl alcohol solution while stirring.

3) Solution viscosity Tetrachloroethane was used as a solvent, and the viscosity was measured at a temperature of 25 ° C. and a concentration of 1 g / dl.

4) Residual sodium content The amount of sodium remaining in the purified polyarylate was measured by atomic absorption spectrometry.

5) Haze The obtained polyarylate was vacuum dried at 120 ° C. for 16 hours and then injection-molded at a cylinder temperature of 380 ° C. and a mold temperature of 130 ° C. to obtain a test piece having a side of 5 cm and a thickness of 3 mm. Molded. The molding machine is 125/75 manufactured by Mitsubishi Heavy Industries, Ltd.
An MST type molding machine was used. AST using this test piece
Based on MD1003, total light transmittance and parallel light transmittance were measured, and haze (turbidity) was calculated. The measurement was performed using SZ-Σ80 type colorimeter manufactured by Nippon Denshoku Co., Ltd.

Example 1 In a reaction vessel equipped with a stirrer, 2,2-bis (4
-Hydroxyphenyl) propane (bisphenol A)
6.0 mol, p-tert-butylphenol 0.3
6 mol, 643 g sodium hydroxide (total OH terminated 1.
(3 times mol) was dissolved in 20 L of water, and then 0.042 mol of tri-n-butylbenzylammonium chloride as a phase transfer catalyst was added and dissolved (aqueous phase). Separately, 1: 1 of terephthalic acid chloride and isophthalic acid chloride
6.36 mol of the mixture were dissolved in 10 L of methylene chloride (organic phase). Keep the reaction vessel at 20 ℃, 500 rp of water phase
The organic phase was added with stirring at m 2. After carrying out a reaction for 4 hours in this state, stirring was stopped and the mixture was allowed to stand for 10 minutes to separate an aqueous phase and an organic phase. After separating the aqueous phase and measuring the volume, 20 L of water and acetic acid were added to the organic phase for neutralization.
Further, the organic phase was washed 5 times with 20 L of water, and then the organic phase was dropped into a large amount of methanol to precipitate the polymer.
The precipitated polymer was isolated and dried.

Examples 2 to 8 All were performed in the same manner as in Example 1 except that the amount of 1: 1 mixture of terephthaloyl chloride and isophthalic acid chloride, the amount of sodium hydroxide and the type of phase transfer catalyst were changed as shown in Table 1. It was

Comparative Example 1 The procedure of Example 1 was repeated except that trimethylbenzylammonium chloride (TMBAC) was used as the phase transfer catalyst.

Comparative Example 2 The procedure of Example 1 was repeated except that triethylbenzylammonium chloride (TEBAC) was used as the phase transfer catalyst.

Comparative Example 3 The same procedure as in Example 1 was carried out except that tripropylbenzylammonium chloride (TPBAC) was used as the phase transfer catalyst.

Comparative Example 4 The same procedure as in Example 1 was repeated except that tri-n-octylmethylammonium chloride (TOMAC) described in Example 1 of JP-B-2-12974 was used as the phase transfer catalyst. Upon addition of the catalyst, the aqueous phase became cloudy and a precipitate was formed at the same time. When this precipitate was analyzed by NMR, it was found to be a complex of bisphenol A and a phase transfer catalyst.

Comparative Example 5 As a phase transfer catalyst, tri-n-octylmethylammonium chloride described in Example 1 of Japanese Examined Patent Publication No. 12974/1990 was used, and when it was increased to 1483 g of sodium hydroxide, it became cloudy even if the catalyst was added. Did not occur. All the subsequent operations were performed in the same manner as in Example 1.

The results of Examples 1-8 and Comparative Examples 1-3 and 5 are shown in Table 1. The relationship between the carboxyl value and the migration rate is shown in FIG.

[0036]

[Table 1]

From Table 1, it is understood that the polyarylate of the present invention has a low carboxyl value, a small amount of residual sodium, and an excellent phase separation property, so that the molded article has excellent optical characteristics. Further, it can be seen from FIG. 1 that the polyarylate of the present invention has a low carboxyl value and thus has excellent phase separation properties.

[0038]

INDUSTRIAL APPLICABILITY As described above, the polyarylate of the present invention has a low carboxyl value, a small amount of residual salts, and excellent optical characteristics, particularly transparency. Therefore, it can be suitably used not only in various optical components but also in fields such as electronic materials. Further, according to the method of the present invention, since the phase separation property between the aqueous phase and the organic solvent phase after the interfacial polymerization is excellent, such a polyarylate can be easily produced.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a carboxyl value and a migration rate.

Claims (2)

[Claims] 1. A polyarylate synthesized from an aromatic diol and an aromatic dicarboxylic acid halide by an interfacial polymerization method, having an inherent viscosity value of 0.35 to 0.80 and a terminal carboxyl value of 20 mol / mol. A polyarylate having a ton amount or less and a residual alkali metal amount of 30 mg / kg or less. 2. A phase transfer catalyst comprising a quaternary ammonium salt of the formula (1) or a phosphonium salt of the formula (2) when performing interfacial polymerization from an alkaline aqueous solution of an aromatic diol and an organic solvent solution of an aromatic dicarboxylic acid halide. The method for producing a polyarylate according to claim 1, wherein the polyarylate is used as a polymer. Embedded image [In the formulas (1) and (2), R _{1 to} R ₃ are n-butyl groups,
R ₄ is an alkyl group such as a methyl group or an ethyl group, or an aromatic substituted alkyl group such as a benzyl group, X is Cl, Br, I, H
Represents SO ₄ . ]